The Tough Calculus of Emissions and the Future of EVs

August 23, 2021

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by Mark Mills (TechCrunch) From materials and batteries to manufacturing, calculating the real carbon cost of EVs is just getting started -- ... While an EV self-evidently emits nothing while driving, about 80% of its total lifetime emissions arise from the combination of the embodied energy in fabricating the battery and then in “fabricating” electricity to power the vehicle. The remaining comes from manufacturing the non-fuel parts of the car. That ratio is inverted for a conventional car where about 80% of lifecycle emissions come directly from fuel burned while driving, and the rest comes from the embodied energy to make the car and fabricate gasoline.

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For example, one review of 50 academic studies found estimates for embodied emissions to fabricate a single EV battery ranged from a low of about eight tons to as high as 20 tons of CO2. Another recent technical analysis put the range at about four to 14 tons. The high end of those ranges is nearly as much CO2 as is produced by the lifetime of fuel burned by an efficient conventional car. Again, that’s before the EV is delivered to a customer and driven its first mile.

The uncertainties come from inherent — and likely unresolvable — variabilities in both the quantity and type of energy used in the battery fuel cycle with factors that depend on geography and process choices, many often proprietary. Analyses of the embodied energy show a range from two to six barrels of oil (in energy-equivalent terms) is used to fabricate a battery that can store the energy equivalent of one gallon of gasoline. Thus, any calculation of embodied emissions for an EV battery is an estimate based on myriad assumptions. The fact is, no one can measure today’s or predict tomorrow’s EV carbon dioxide “mileage.”

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The inherent energy density of lithium-class chemicals (i.e., not a battery cell, but the raw chemical) can be theoretically as high as about 700 watt-hours per kilogram (Wh/kg). While that’s roughly fivefold greater than the energetics of lead-acid battery chemistry, it’s still a small fraction of the 12,000 Wh/kg available in petroleum.

To achieve the same driving range as 60 pounds of gasoline, an EV battery weighs about 1,000 pounds.

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Manufacturers offset some of a battery’s weight penalty by lightening the rest of the EV using more aluminum or carbon fiber instead of steel. Unfortunately, those materials are respectively 300% and 600% more energy intensive per pound to produce than steel. Using a half ton of aluminum, common in many EVs, adds six tons of CO2 to the non-battery embodied emissions (a factor most analyses ignore). But it’s with all the other elements, the ones needed to fabricate the battery itself, where the emissions accounting gets messy.

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Depending on the specific formulation chosen, the embodied energy associated with the key battery chemicals themselves can vary by as much as 600%.

Consider the key elements in the widely used nickel-cobalt formulation. A typical 1,000-pound EV battery contains about 30 pounds of lithium, 60 pounds of cobalt, 130 pounds of nickel, 190 pounds of graphite and 90 pounds of copper.

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Putting all the factors together, fabricating a single half-ton EV battery can entail digging up and moving a total of about 250 tons of earth. After that, an aggregate total of roughly 50 tons of ore are transported and processed to separate out the targeted minerals.

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Remote mining sites typically involve more trucking and depend on more off-grid electricity, the latter commonly supplied by diesel generators. As it stands today, the mineral sector alone accounts for nearly 40% of global industrial energy use. And over one-half of the world’s batteries, or the key battery chemicals, are produced in Asia with its coal-dominated electric grids.

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The calculations showed that, compared to a fuel-efficient conventional car, an EV’s lifecycle emissions can range from as much as 60% lower when driven in Norway or France, to about 25% lower when driven in the U.K., to tiny emissions reduction if driven in Germany. (Germany’s grid has roughly the same average carbon emissions per kilowatt-hour as does America’s.)

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While the EV time factor has minimal variability in Norway and France where most electricity comes around the clock from hydro and nuclear respectively, it can vary wildly elsewhere from, say, 100% solar to 100% coal depending on the time of day, month and location.

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IEA (amongst others) reports that most mineral production today entails processes at the higher end of emissions “intensity.” Adjusting the ICCT outcomes for that reality lowers the calculated lifecycle EV emissions savings to about 40% (instead of 60%) driving in Norway, to little or no reduction in the U.K. or the Netherlands, and about a 20% increase for EVs driven in Germany.

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The ICCT, again typical of many similar analyses, made calculations based on batteries 30% to 60% smaller than the size required to replicate the 300-mile range needed for widespread replacement of conventional cars. The larger batteries are common on high-end EVs today. Doubling the size of the battery leads to a straightforward doubling of its carbon debt which, in turn, dramatically erodes or eliminates lifecycle emissions savings in many, maybe most places.

Similarly problematic, one finds forecasts of future emissions savings often explicitly assume that the future battery supply chain will be located in the country where the EVs operate.

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Compared to conventional cars, EVs require using, overall, about 500% more critical minerals per vehicle. Thus, the IEA concludes that current plans for EVs, along with plans for wind and solar, will require a 300% to 4,000% increase in global mine output for the necessary suite of key minerals.

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To illustrate the ultimate scale of demand that EV mandates alone will place on mining, consider that a world with 500 million electric cars — which would still constitute under half of all vehicles — would require mining a quantity of energy minerals sufficient to build batteries for about 3 trillion smartphones. That’s equal to over 2,000 years of mining and production for the latter. For the record, that many EVs would eliminate only about 15% of world oil use.

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The IEA sees, for example, a 300% to 600% increase in emissions to produce each pound of lithium and nickel respectively.

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Commercially viable combustion engines already exist that can cut fuel use by as much as 50%. Capturing just half that potential by providing incentives for consumers to purchase more efficient engines would be cheaper, faster — and transparently verifiable — than adding 300 million EVs to the world’s roads. READ MORE

RENEWABLES PAY MORE: (Politico's Morning Energy)

The Energy Future Needs Cleaner Batteries (Bloomberg Green)

How the rise of copper reveals clean energy’s dark side (The Guardian)

Hunt for the ‘Blood Diamond of Batteries’ Impedes Green Energy Push (New York Times)

Nissan, Burned by Experience, Shuns Bold EV Forecasts--Car maker sees uncertainty in U.S. but more rapid shift to battery-powered vehicles in Europe, China (Wall Street Journal)

Federal Government Backs Increasing Domestic Minerals Supply Chain Needed for EVs (NGT News)

Excerpt from Politico's Morning Energy: RENEWABLES PAY MORE: Transmission upgrade costs are disproportionately shouldered by new wind and solar projects, even though their benefits are enjoyed by many power industry players, according to a new report from the American Council on Renewable Energy. The analysis comes as FERC grapples with how to reform U.S. transmission policy, and Glick has said cost allocation questions are expected to be particularly thorny. Projects that upgrade power lines can reduce congestion and allow more renewables onto the grid, but saddling a single generator with the high costs can discourage companies from wanting to connect to the grid at all. READ MORE